Editor's note: Amy Gahran writes about mobile tech for CNN.com. She is a San Francisco Bay Area writer and media consultant whose blog, Contentious.com, explores how people communicate in the online age.

(CNN) -- Over the last decade, more news has been getting out from, and reaching into, North Korea via smuggled cell phones. These are mainly used in border areas where cell signals from neighboring countries are available.

Unlicensed cell phones are illegal in the reclusive dictatorship, yet many North Koreans have been able to obtain and use them. But this practice now poses greater risks than ever.

Some news outlets that cover the Korean peninsula are reporting that North Korea has launched a drive to confiscate unlicensed cell phones.

Citing the latest newsletter from North Korea Intellectuals Solidarity (a group of dissident defectors), China Post reported last week that "Police in North Hamkyong and Yangkang provinces bordering Russia and China have started urging residents to voluntarily surrender mobile phones or face punishment.

"The police warned that special devices to detect mobile phone use had been brought in to punish 'those spreading capitalist ideas and eroding socialism,' according to one of the group's sources."

Why now? North Korea is widely believed to be readying to hand off leadership from Kim Jong Il to his son Kim Jong-Un. Probably not coincidentally, this week Amnesty International reports that North Korea's brutal political prisons are growing.

The impending leadership shift probably isn't the only reason for North Korea's crackdown on unlicensed cell phones.

Mobiledia observed: "Sources say the government is restricting the flow of information even more carefully than before in the wake of recent Middle East uprisings."

On a related note, according to the Korea Herald, the government in Pyongyang has ordered the more than 200 North Koreans working in Libya not to return home, "apparently out of fear that they will spread news of the anti-government uprisings in the African nation."

In recent months, North Korea also suspended its cell phone rental service for visiting foreigners, just as "Arab Spring" revolutions were toppling dictatorships throughout North Africa and the Middle East.

"North Korean authorities routinely seize foreign visitors' mobile phones at Pyongyang airport or elsewhere and return them as they leave the country. Until last year, foreign visitors were allowed to rent mobile phones capable of making international calls -- but recent visitors quoted North Korean officials as saying the country has restricted rentals to foreign residents only since January."

The North Korean government's fears of consumer communications and media technology is not limited to cell phones.

In April, Korea Herald reported: "Pyongyang has ordered institutions and households to report on how many computers and even portable data storage devices such as USBs and MP3 players they own early this year, according to a Seoul government source."

Cell phones -- at least, legally licensed ones -- are surprisingly popular in North Korea. Last month PC World reported that North Korea's state-run cell phone network, Koryolink, has more than 430,000 subscribers, nearly 2% of the North Korean population.

Koryolink is available in Pyongyang, 14 other North Korean cities and along 22 major highways. It provides voice and video phone service, text and multimedia messaging, and 3G data service. However, subscribers cannot place international calls or access the Internet from their phones.

The blog North Korean Economy Watch speculated that Koryolink mobile data customers can connect only to North Korea's homegrown self-contained computer network, Kwangmyong.

Ironically, since Koryolink is the only official wireless carrier there, North Korea recently topped a global list for having the world's greatest percentage of mobile subscribers on 3G.

The number of unlicensed illegal cell phones in North Korea is unknown.

Last November, in an article about a clandestine Asia Press citizen journalism project in North Korea, IT World noted: "Signals from Chinese cellular towers reach a few kilometers into North Korea and are difficult to monitor by the state's telecom surveillance operation. ... (But now), mobile detection units patrol the border looking for signals from within North Korea and, if found, attempt to triangulate their source.

"If caught, the punishment can be severe. Earlier this year a man faced a public firing squad after he was caught with a cell phone and admitted to supplying information to someone in South Korea, according to a report by Open Radio for North Korea."